I'd also add this: First impressions are really important.
Despite the fact that it was broken as hell on release day, MK9 was just so cool. It looked good, it had everyone's favorite characters, it reminded us of the arcade MK's, etc... Most realized how the game has potential, how fluid it was, how great the movement is (though of course you had the usual "it has no footsies, no anti airs, etc..." talk that was proven to be nonsensical later on). To be clear, I'm strictly talking about the NRS community here. Capcom guys dropping the game means nothing. Our community embraced the game, for the most part, even through the inevitable moaning and crying. For a lot of us, MK9 popped our fighting game cherry, and that only happens once (I think
).
Injustice in my opinion, fell flat at first. The reaction for the most part within the community was, on average, quite lukewarm, and that includes many top players whose opinions hold weight and influence. Like MK9, the game had a lot of broken bullshit, but unlike MK9, it didn't benefit from everyone's willingness to tolerate it while waiting for the patches because they're just so passionate about it. As a result, the complaints about the game were constant, and the criticism was extremely vocal. The Deathstroke debacle, the metropolis rooftop debacle, the infamous Scorpion debacle, the F23 skill-gap debacle, etc...surely didn't help. After EVO 2013 when MK9 started its official fading out phase, most were emo. It was like having to deal with a break up with your longtime girlfriend and not quite warming up to the rebound chick. Now a few months later the rebound chick ended up being quite awesome (I can't stress how awesome the October patch was, though I'm not saying the game is perfect), but by then, for many, it was still difficult to shake off that first impression and the constant (needless) comparisons with MK9. Hence the outdated narratives of the game having no footsies, no anti-airs, etc...
Also, propaganda matters. Tournament players who were unable to accept their relative lack of success (compared to MK9) being so outspoken and blaming the game for their shortcomings couldn't have helped. These things leave an impression on people, and many will mindlessly repeat what they hear, or at least allow it to distort perception. That, coupled with much of the above explains that negative vibe that's been constantly there since the release of Injustice. It's a shame really, as I think NRS did a really great job.
With that said, things are getting overblown. Those who still play and enjoy the game still support it, and they're hardly so few. Tournaments are still exciting (and before anyone says: "Not really because Sonic Fox," think of REO's reign of terror in MK9 in the second of half of 2012, so that's not quite exclusive to the Injustice tournament scene), and people ARE still playing the game. Let's not blow things out of proportion. A lot of people act like some of the issues with Injustice are unheard of. Really? Top tier characters in fighting games are a novelty now all of a sudden? Aquaman's trident rush is any more or less dumb than Kabal's entire move set, Kenshi's armor, Sonya's ex cartwheel, etc...? Sonic Fox winning everything is some sort of unheard of event? Dominant players never existed in other fighting games? Theo and Aquaman win every WNF? Let me ask this, if REO was somehow a West Coast player (hypothetically) and WNF hosted MK9 weeklies back in the game's heyday, you don't think he would have won pretty much every week? Would the usual suspects drop the game because of REO and Kabal? At this point, the naysayers will look for anything to say "lol Injustice who cares. lol Martian. lol Aquaman. lol Sonic Fox." It's annoying as hell.